Appearing on the March cover of Marie Claire, the 27-year-old actress -- who wouldn't make a bad Duchess of Cambridge in a screen adaptation -- says she's unabashedly thrilled about the upcoming birth of Britain's future monarch. She's less enthusiastic, however, about the system of monarchy itself.

"I'm over the moon about the royal baby," she gushes to the magazine. "But I really can't mount an argument in favor of the monarchy. Is that treason? Do I have to turn in my passport?"

The Anna Karenina star has always been an independent thinker. And she gravitates toward other independent thinkers, too. Speaking about her fiance, Klaxons keyboardist James Righton, she notes that what makes them so compatible isn't their similarities but their differences.

"I get wonderful perspective by being with someone who is less like me than more like me," she tells Marie Claire of her husband-to-be. "The way he thinks is something I don't get. We come at things from totally different angles."